Most players are at least vaguely
familiar with pentatonic scales.They're used in all kinds of music
all over the world.Jazz players often use a pentatonic
scale as a melodic device, but overlook its harmonic possibilities.Since this scale isn't entirely
made up of steps, some interesting voicings result from harmonizing it.One reason for pentatonic scales'
popularity is that they can be used over many different tonal centerswithout too many "avoid notes",
notes that sound bad against a chord.This property of the scales also
makes them useful for comping.

For our purposes, let's examine the
A minor pentatonic scale (A-C-D-E-G).Many of us first encountered this
scale in a rock or blues context;it has many other potential applications!

First, let's harmonize the scale
in 3-note voicings:Note how we automatically get triads
interspersed with "cluster" voicings. Cool.The sound of those close intervals
may take some getting used to.Bar 1 is in root position; bars
2 + 3 are 1st and 2nd inversions.In the last bar, I spread the voicings
from the first group:I moved the middle voice up to the
top (and also moved the whole voicing down an octave).All the inversions could be spread-voiced
as well; try it...

Here are some playable 4-note voicings.Analyze all these voicings; most
of them could be used in many ways!For example, the 2nd voicing shown
could be used as:F6/9, Am7sus4, Dm7sus4, Bbmaj13,
C6/9, F#7alt, Gm9sus4, and a few other things!

Below is a table showing several
chords to which the A minor pentatonic scale can be related:

A

C

D

E

G

Am

root

3rd

4th (11th)

5th

7th

C,
C7, C9,etc.

6th (13th)

root

2nd (9th)

3rd

5th

Gm

2nd (9th)

4th (11th)

5th

6th

root

Dm

5th

7th

root

2nd (9th)

4th (11th)

D7sus4

5th

7th

root

2nd (9th)

4th (11th)

F

3rd

5th

6th

7th

2nd (9th)

Bb

7th

2nd (9th)

3rd

#11

6th

F#7alt

#9th

b5th

#5th

7th

b9th

There are others, but this'll do
for now.Of course, it'd be pretty tough
to memorize this table, so here are a few hints.You can use this pentatonic scale
harmonically just as you might use it melodically:

A Few Hints:• On a minor chord, you can
use a minor pentatonic scale starting from the chord's root, 2nd, or 5th.• On a major chord, you can
use a minor pentatonic scale starting from the chord's 3rd, 6th (or 7th
for a Lydian [#11] sound).• On an unaltered dominant 7th
chord or 7sus4, you can use a minor pentatonic scale starting from
the chord's 2nd, 5th or 6th.• On an altered dominant 7th,
you can use a minor pentatonic scale starting from the chord's #9.

Okay, let's look at some musical
examples now.In the first couple of examples,
we'll continue to use the A minor pentatonic over a set of changes.Then we'll get into mixing and matching
different minor pentatonics using the guidelines above.In example 1, we have a common
ii-V7-I progression, all handled with the A minor pentatonic scale.

Notice the ambiguous, "open" sound
a lot of these voicings have.Many of these voicings lack "guide
tones", which is OK in a group context; someone else'll likely be playing
the guide tones.In real life, you'll probably find
this pentatonic approach most satisfying when mixed with other types of
voicings.Too much ambiguity can get tedious
eventually...

Example 2 is a I-IV-iii-VI
progression in F major. Note the #11 sound on the IV.Again, we're using only voicings
from A minor pentatonic.

Now we're going to start using voicings
from more than one minor pentatonic scale.I've labeled the scale choices;
check them against the "hints" above to see how I chose the scales.

Example 3:

In spots where the harmony doesn't
change much, using alternate pentatonic choices can liven up the sonic
landscape.In example 4, I used Dm,
Em and Am pentatonics to play over a long stretch of D minor.(This example's not too interesting
rhythmically; I wanted to cram in a lot of voicings!)Try voicings like this next time
you play "Impressions" or "So What".

"But, Bob," I can hear you
saying, "don't all these voicings exist in the C major scale?"Well, sure they do, but what makes
them sound different is that we're leaving out certain notes in the major
scale,or, more accurately, choosing to
concentrate on only some of the notes at a time.

As I implied earlier, I doubt I'd
play a whole tune using nothing but pentatonic harmony,but this method can open up some
interesting sounds.Used judiciously, it can provide
a nice contrast to tertian [third-based] harmony.Enjoy...